簡介 
在Ext官方的例子中只有下拉列表控件,但是在實際業務中只有下拉列表無法滿足需求的,像下拉樹和下拉表格都是很常見的控件,對于剛使用Ext的人來說,自定義一個控件好難,其實多讀官方的源碼有些事情就不會那么難了。下面是下拉樹的代碼: 
 
Ext.define('ComboTreeBox',{ 
extend : 'Ext.form.field.ComboBox', 
multiSelect : true, 
createPicker : function(){ 
var me = this; 
//創建樹控件 
var picker = Ext.create('Ext.tree.Panel', { 
store: me.store, 
rootVisible: false, 
selModel: { 
mode: me.multiSelect ? 'SIMPLE' : 'SINGLE' 
}, 
floating: true, 
hidden: true, 
focusOnToFront: false 
}); 
//注冊事件用于選擇用戶選擇的值 
me.mon(picker, { 
itemclick: me.onItemClick, 
refresh: me.onListRefresh, 
scope: me 
}); 
me.mon(picker.getSelectionModel(), { 
beforeselect: me.onBeforeSelect, 
beforedeselect: me.onBeforeDeselect, 
selectionchange: me.onListSelectionChange, 
scope: me 
}); 
this.picker = picker; 
return picker; 
}, 
onItemClick: function(picker, record){ 
/* 
* If we're doing single selection, the selection change events won't fire when 
* clicking on the selected element. Detect it here. 
*/ 
var me = this, 
selection = me.picker.getSelectionModel().getSelection(), 
valueField = me.valueField; 
if (!me.multiSelect && selection.length) { 
if (record.get(valueField) === selection[0].get(valueField)) { 
// Make sure we also update the display value if it's only partial 
me.displayTplData = [record.data]; 
me.setRawValue(me.getDisplayValue()); 
me.collapse(); 
} 
} 
} 
}); 
 
下拉樹的代碼很簡單,只要集成Ext.form.field.ComboBox類,然后重寫createPicker方法就可以了,同理下拉表格也是如此,下面是下拉表格的代碼: 
 
Ext.define('ComboGridBox',{ 
extend : 'Ext.form.field.ComboBox', 
multiSelect : true, 
createPicker : function(){ 
var me = this; 
var picker = Ext.create('Ext.grid.Panel', { 
title : '下拉表格', 
store: me.store, 
frame : true, 
resizable : true, 
columns : [{ 
text : '#ID', 
dataIndex : 'id' 
},{ 
text : '名稱' , 
dataIndex : 'name' 
},{ 
text : '描述' , 
dataIndex : 'desc' 
}], 
selModel: { 
mode: me.multiSelect ? 'SIMPLE' : 'SINGLE' 
}, 
floating: true, 
hidden: true, 
width : 300, 
columnLines : true, 
focusOnToFront: false 
}); 
me.mon(picker, { 
itemclick: me.onItemClick, 
refresh: me.onListRefresh, 
scope: me 
}); 
me.mon(picker.getSelectionModel(), { 
beforeselect: me.onBeforeSelect, 
beforedeselect: me.onBeforeDeselect, 
selectionchange: me.onListSelectionChange, 
scope: me 
}); 
this.picker = picker; 
return picker; 
}, 
onItemClick: function(picker, record){ 
/* 
* If we're doing single selection, the selection change events won't fire when 
* clicking on the selected element. Detect it here. 
*/ 
var me = this, 
selection = me.picker.getSelectionModel().getSelection(), 
valueField = me.valueField; 
if (!me.multiSelect && selection.length) { 
if (record.get(valueField) === selection[0].get(valueField)) { 
// Make sure we also update the display value if it's only partial 
me.displayTplData = [record.data]; 
me.setRawValue(me.getDisplayValue()); 
me.collapse(); 
} 
} 
}, 
matchFieldWidth : false, 
onListSelectionChange: function(list, selectedRecords) { 
var me = this, 
isMulti = me.multiSelect, 
hasRecords = selectedRecords.length > 0; 
// Only react to selection if it is not called from setValue, and if our list is 
// expanded (ignores changes to the selection model triggered elsewhere) 
if (!me.ignoreSelection && me.isExpanded) { 
if (!isMulti) { 
Ext.defer(me.collapse, 1, me); 
} 
/* 
* Only set the value here if we're in multi selection mode or we have 
* a selection. Otherwise setValue will be called with an empty value 
* which will cause the change event to fire twice. 
*/ 
if (isMulti || hasRecords) { 
me.setValue(selectedRecords, false); 
} 
if (hasRecords) { 
me.fireEvent('select', me, selectedRecords); 
} 
me.inputEl.focus(); 
} 
console.log(me.getValue()); 
}, 
doAutoSelect: function() { 
var me = this, 
picker = me.picker, 
lastSelected, itemNode; 
if (picker && me.autoSelect && me.store.getCount() > 0) { 
// Highlight the last selected item and scroll it into view 
lastSelected = picker.getSelectionModel().lastSelected; 
itemNode = picker.view.getNode(lastSelected || 0); 
if (itemNode) { 
picker.view.highlightItem(itemNode); 
picker.view.el.scrollChildIntoView(itemNode, false); 
} 
} 
} 
}); 
 
下拉表格也是繼承了Ext.form.field.ComboBox這個類,重寫了createPicker方法。 
開發下拉樹和下拉表格看起來so easy,只要研究透了Ext的運行機制,一切都會so easy 
控件效果 
 
 

實例下載 
實例中的資源為myeclipse項目,導入即可運行,自己添加ext的js和css文件,實例中沒有ext的基礎文件。 
下載地址